High-risk sports activities in our study included trampoline jumping, jumping, weightlifting, and fast and slow running. For our research, we required a device that could examine pelvic floor demand expressed by the VPP during these sports activities.

No study to date has measured urine leakage in grams during standardised high-risk sports activities. We also decided to develop a new pad test to quantify urine leakage during these activities in female athletes. Our female athletes experienced urine leakage only during sports, not during normal activities. No urine leakage would have been observed using the standard pad test. The newly developed iPWT can be used to investigate the association of urine leakage with the VPP.

In the main measurements of our study, we found that as intra-abdominal pressure rose, intravaginal pressure also rose, increasing the load on the pelvic floor. The pressure threshold for developing or worsening pelvic floor dysfunction remains unknown and is likely to vary between individuals.

Measuring the changes in the vaginal pressure profile (VPP) during a variety of sports will help with our understanding of the magnitude of pressures developed during such activities and the response of the pelvic floor to those pressures. In turn, this could aid in selecting safe exercises for women with pelvic floor dysfunction. Few studies have been published on measuring VPPs during sporting activities [15,16,17,18,19]. No study to date has measured urine leakage in grams during high-risk sports activities using a newly created pad test. Only standard pad tests have been used, but they do not assess high-intensity physical activity [20, 21]. High-risk sports activities in our study included trampoline jumping, jumping, weightlifting, and fast and slow running. We selected these activities based on a systematic review and meta-analysis [9].

The primary aim of this pilot study was to measure changes in the VPP using the Femfit® during high-risk sports activities in elite female athletes with and without SUI and to determine if there were differences between the two groups. The secondary aim was to quantify the amount of urine leakage during the activities using the newly created iPWT.

In our cohort, we had ten nulliparous female athletes with a mean age of 20 years who engaged in high-intensity physical activity.

The results suggest that the ability of the pelvic floor to respond sufficiently to increases in IAP during high-intensity activity appears to be reduced in athletes with SUI. The higher intravaginal pressures measured while jumping on the trampoline corresponded to the most urine leakage in athletes with SUI, which is unsurprising because previous research has shown that female trampolinists often experience the highest incidence of SUI. Jumping on a trampoline causes a very strong continuous increase in intra-abdominal pressure [17].

Interestingly, lower IVP overall was observed for weightlifting (25% of body weight), yet those athletes with SUI still had a higher volume of leakage during this activity, suggesting there is perhaps a threshold for leakage that is dependent on more than just pressure generation. However, these results should be interpreted with caution due to the small sample size.

In an observational prospective study, Kruger [18] measured vaginal pressures with Femfit® in 24 women with a mean age of 37.5 years during exercises that may also have a negative impact on the pelvic floor. This study evaluated planks, bicycling, running, walking, push-ups, lunges and squats. Running, push-ups, squats and standing cycling produced higher pressures on all sensors than equivalent safe pelvic floor exercises. IVP was highest during running. However, the pressure threshold for the development or worsening of pelvic floor dysfunction remains unknown and is likely to be individual-specific. In our study, we observed the highest IVP with ground and trampoline jumps.

Cacciari [17] tested intravaginal pressure changes using Femfit® in 20 healthy women during the contraction of the PFMs and during the Valsalva manoeuvre in the supine and standing positions. They were compared with maximal voluntary contraction assessed by dynamometry and palpation through the vagina. A positive significant correlation was found between IVP and both dynamometry and vaginal palpation.

Shaw [24] measured IAP in 57 women while performing different types of physical activity using a different measuring device – The Gen2 Intravaginal transducer. The women performed 31 sports activities at light, moderate and high intensities. IAP was measured during coughing, Valsalva, lying down, sitting and during aerobic activities, including walking, running, cycling and stepping. Other measurements were taken while performing daily activities, lifting tasks, stabilisation exercises and stretching activities. An important finding was that coughing had a high maximum pressure of 199.9 cmH2O (153.7 mmHg) than the other activities. The seated Valsalva had a similarly high maximum pressure of 207.7 cmH2O (159.7 mmHg) compared to the other activities. In our study, we recorded the highest average 64.8 mmHg, with ground and trampoline jumps.

These results imply that it is important to recognise the magnitude of IAP but also the response of the pelvic floor to that increase in pressure.

The secondary aim of this study was to quantify the amount of urine leakage using an iPWT.

The meta-analysis showed a 25.9% prevalence of urinary incontinence in female athletes in different sports, as well as a 20.7% prevalence of SUI. The most prevalent high-impact sport was volleyball, with a value of 75.6%, then jumps on the trampoline at 72.7% and running at 44.0%. On the basis of the above meta-analysis, we selected the most risky movement activities for the iPWT [9].

Several authors have used a standard 1-h pad test in their studies, including slow walking, standing from sitting, coughing, running in place, standing from lying down and hand washing. The pad is weighed after the entire test, not after each activity. Except for coughing, it did not include any activity that would significantly increase IAP [25].

We measured urinary leakage symptoms with the ICIQ UI SF questionnaire, and the mean score confirmed moderate urinary leakage. The overall sum of the mean urine leakage measurements from the five sports activities was 6.60 g. We created an iPWT to test urine leakage during each sports activity mentioned above. Five measurements were taken for each patient; thus, the average values were obtained from 50 measurements. On average, 1.40 g of urine leakage was measured during each activity: trampoline jumping, weightlifting and slow running. Meanwhile, 1.20 g urine leakage, on average, was measured during ground jumping and fast running.

The primary limitation of this study is the small number of participants, which means the conclusions should be interpreted with caution. The study’s strengths include the development of the newly created iPWT and its application during five types of high-risk sports activities. Another strength is the use of a device capable of examining pelvic floor demand, as expressed by the VPP, during these sports activities in female athletes with and without SUI.